An aerial view shows people cooling off at a swimming pool on a hot summer day in Haltern, Germany, July 1, 2015. A widespread, long-lasting heatwave will affect much of France, Britain, Belgium, the Netherlands and western Germany. Forecast highs on Wednesday could reach 35 degrees Celsius (95 degrees Fahrenheit). REUTERS/Ina Fassbender

An aerial view shows people cooling off at a swimming pool on a hot summer day in Haltern, Germany, July 1, 2015. A widespread, long-lasting heatwave will affect much of France, Britain, Belgium, the Netherlands and western Germany. Forecast highs on Wednesday could reach 35 degrees Celsius (95 degrees Fahrenheit). REUTERS/Ina Fassbender